As is known, the pharmaceutical industry has had limited success overcoming the challenges of delivering pharmaceuticals to patients. The oral ingestion of pharmaceuticals is considered the safest, most convenient and most economical method of drug administration. As compared to present alternatives, patient acceptance and adherence to a dosing regimen is typically higher among orally delivered pharmaceuticals. However, the oral delivery of many pharmaceuticals is not possible because the pharmaceutical molecule is either too large or too electrically charged to pass through the small intestine to reach the bloodstream. In addition, many pharmaceuticals that are unable to withstand the environment of the digestive tract or to penetrate the dermis need to be injected into the patient (e.g. insulin, proteins). As hereinafter described, the injection of pharmaceuticals into a patient has certain drawbacks.
By way of example, insulin is often used to treat diabetes, a disorder of metabolism. Most of the foods eaten by individuals are broken down in the body into glucose, the form of sugar in the blood. Glucose is the main source of fuel for the body. After digestion, the glucose passes into the bloodstream where it is used by the cells for growth and energy. For glucose to get into cells, insulin must be present. Insulin is a hormone that is automatically produced by a healthy pancreas to move glucose from blood into our cells. In people with diabetes, however, the pancreas either produces little or no insulin, or the cells do not respond appropriately to the insulin that is produced. As a result, glucose builds up in the blood, overflows into the urine, and passes out of the body. Consequently, the body loses its main source of fuel, even though the blood contains large amounts of glucose.
In order to use the glucose present in the body, a diabetic must take insulin injections every day. The amount of insulin taken by an individual must be balanced with the individual's food intake and daily activities. Consequently, blood glucose levels must be closely monitored through frequent blood glucose checking to insure that blood glucose levels do not fall too low or rise too high. When blood glucose levels drop too low from certain diabetes medicines—a condition known as hypoglycemia—a person can become nervous, shaky, and confused. If blood glucose falls, judgment can be impaired and a person could faint. Alternatively, a person can also become ill if blood glucose levels rise too high, a condition known as hyperglycemia. Although daily insulin injections are a great inconvenience, they are necessary for a diabetics' survival.
Most people with diabetes administer their own insulin after learning the proper techniques for insulin preparation and injection. The goal of insulin administration is to give enough insulin to cover the amount of food (especially carbohydrates) that a person consumes so that blood glucose levels remain normal throughout the day and night. It can be appreciated that various factors such as the type of insulin used, the size of the person, the amount, type, and time that meals are eaten, and the activity and exercise patterns of the person affect the amount of insulin that is required by an individual. It takes a dedicated patient to continually monitor their blood glucose level and administer the repeated multiple injections required. Therefore, an autonomous infusion system that provides a steady infusion of pharmaceuticals to an individual when needed would constitute a significant advancement in the art.
Therefore, it is a primary object and feature of the present invention to provide a bladder arrangement for a microneedle-based, active transdermal drug delivery device that allows for the delivery of a steady infusion of a pharmaceutical to an individual when needed.
It is a further object and feature of the present invention to provide a bladder arrangement for a microfluidic, drug delivery device that allows for the delivery of a infusion of a pharmaceutical to an individual that is simple to utilize and inexpensive to manufacture.
In accordance with the present invention, a bladder arrangement is provided for a microfluidic drug delivery device. The bladder arrangement includes a first flexible membrane having an inner and outer surface. A rigid bladder member includes an inner surface and an outer surface. The inner surface of the flexible membrane and the inner surface of the rigid bladder member defines a chamber for receiving a drug therein. The bladder arrangement further includes at least one microneedle and a valve arrangement operatively connecting the at least one microneedle to the rigid bladder member. The valve arrangement has a first configuration wherein the at least one microneedle is fluidically isolated from the drug in the chamber and a second configuration wherein the at least one microneedle fluidically communicates with the drug in the chamber.
The first flexible membrane has an outer periphery and the rigid bladder member has an outer periphery. The outer periphery of the first flexible membrane and the outer periphery of the rigid bladder member are bonded to form a hermetic tight seal. It is contemplated for the at least one microneedle is one of an array of microneedles. The rigid bladder matter includes an opening therethrough for allowing the drug to be injected into the chamber. A plug is receivable in the opening in the rigid bladder matter for maintaining the drug in the chamber. The valve arrangement may include a check valve. The check valve allows the drug to flow in a first direction from the chamber to the at least one microneedle and prevents fluid flow in a second direction from the at least one microneedle to the chamber.
In accordance with a further aspect of the present invention, a bladder arrangement is provided for a microfluidic drug delivery device. The bladder arrangement includes a flexible membrane having an inner surface, an outer surface and an outer periphery. A rigid bladder member includes an inner surface, an outer surface and an outer periphery bonded to the outer periphery of the flexible membrane. The inner surface of the flexible membrane and the inner surface of the rigid bladder member define a chamber for receiving a drug therein. At least one microneedle is operatively connected to the rigid bladder member. A valve arrangement controls the flow of the drug from the chamber to the at least one microneedle.
The outer periphery of the flexible membrane and the outer periphery of the rigid bladder member are bonded to form a hermetic seal. It is contemplated for the at least one microneedle to be one of an array of microneedles. The rigid bladder member includes an opening therethrough for allowing the drug to be injected into the bladder and wherein the bladder arrangement further comprises a plug receivable in the opening in the rigid bladder matter for maintaining the drug in the chamber. The valve arrangement includes a check valve. The check valve allows the drug to flow in a first direction from the chamber to the at least one microneedle and preventing fluid flow in a second direction from the at least one microneedle to the chamber. A pressure source is engageable with the flexible member for urging the drug from the chamber to the at least one microneedle. The pressure source includes an expandable hydrogel. The hydrogel applies pressure on the flexible member as the hydrogel expands.
In accordance with a still further aspect of the present invention, a bladder arrangement is provided for a microfluidic drug delivery device. The bladder arrangement includes a flexible membrane having an inner surface, an outer surface and an outer periphery. A rigid bladder member includes an inner surface, an outer surface and an outer periphery. The inner surface of the flexible membrane and the inner surface of the rigid bladder member define a chamber for receiving a drug therein. At least one microneedle is operatively connected to the rigid bladder member. The at least one microneedle has an input and an output receivable within the individual. A valve is operatively connected the input of the at least one microneedle and the chamber.
A pressure source is engageable with the flexible membrane for urging the drug from the chamber through the at least one microneedle. The outer periphery of the flexible membrane and the outer periphery of the rigid bladder member are bonded to form a hermetic tight seal. The at least one microneedle is one of an array of microneedles and the rigid bladder matter may include an opening therethrough for allowing the drug to be injected into the chamber. A plug is receivable in the opening in the rigid bladder member for maintaining the drug in the chamber. It is contemplated for the valve to be a check valve. The check valve allows the drug to flow in a first direction from the chamber to the at least one microneedle and prevents fluid flow in a second direction from the at least one microneedle to the chamber. A docking station may be used to support the at least one microneedle. The docking station is removably connected to the rigid bladder member.